Research results show that female frogs ``pretend to be dead'' to avoid unwanted mating


of European red frogs , which are widely distributed in Europe, gather in ponds during the breeding season, and multiple males engage in fierce competition over a single female. Scientists previously believed that female European red frogs did not refuse mating requests from males, but new research suggests that females may use tactics such as 'playing dead' to engage in unwanted mating. It turns out to be avoided.

Drop dead! Female mate avoidance in an explosively breeding frog | Royal Society Open Science

Tired of aggressively amorous males? These female frogs play dead | Science | AAAS

These female frogs fake their own deaths to get out of sex | Live Science

Female frogs appear to fake death to avoid advances unwanted, study shows | Animal behavior | The Guardian

Mating in European red frogs is done in a way where multiple males compete for one female, creating a state called a mating ball where multiple individuals are crowded together. Intense mating in such conditions often puts a strain on the female's body, and sometimes many individuals cover the female and cause her to drown. ``In some cases, females are killed in the mating balls,'' said Carolin Dietrich, a researcher at the Berlin Museum of Natural History.

Until now, it has been thought that females do not have the means to protect themselves from violent mating by males, and simply respond to male mating. However, when Dietrich and his colleagues conducted an experiment to find out whether male European red frogs show a preference for female physical differences, they found that females behaved as if to avoid mating with males. did.

The research team prepared ``large-bodied females'' and ``small-bodied females'' of European red frogs during the breeding season, placed them in an aquarium, and placed a male during the breeding season there for an hour to photograph the frogs. The research team hypothesized that ``male males prefer larger females because they can lay more eggs,'' but they found that males mate based on size. No tendency to select females was observed.

However, when Dietrich et al.'s research team checked the footage during the experiment, they found that female frogs use three tactics to avoid males seeking mating.

The first tactic used by female European red frogs is to turn around on their backs when grabbed by a male. This causes the covered male to sink into the water and drown, so the male releases the female's body. In an experiment, it was reported that 83% of the 54 females grabbed by males turned on their backs.

The second tactic was to emit two types of calls when mounted by a male, and 48% of females mounted by a male used this tactic. The lower of the two cries is thought to imitate the cries that males make to warn other males, but it is unclear what the purpose of the higher cries is.

The third tactic is that when mounted by a male, they lie down with their arms and legs stretched out for about two minutes and pretend to be dead. 33% of females mounted by males played dead and began swimming again after the males lost interest.

It should be noted that ``playing dead'' tended to occur at the same time as the first evasive behavior of ``turning on your back'' and that smaller females were more likely to use these tactics. Reported. Overall, 46% of females escaped from the male's mount, and smaller females were more likely to escape from male mating.

The research team points out that the ``playing dead'' observed this time is not necessarily done intentionally by the female, but may be due to a stress response. In this case, the younger, smaller females may have less mating experience and may therefore be under more stress from being mounted by a male, resulting in them feigning death more frequently. 'It seems to us that the female is playing dead, but we can't prove that this is a conscious behavior. It could be an automatic response to stress,' Dietrich said. I am.

This experiment was limited by the small sample size, the fact that the environment was different from the natural environment, and the fact that there was only one male. Dietrich points out that females may also be able to escape from males more easily because there are more places to hide in wild environments.

However, this study provides a new perspective, showing that female European spotted frogs can not only obey males but also refuse to mate with males. 'Even though we call this species the 'common frog' and think we know it well, I think there are aspects of this species that we don't know about and perhaps haven't even thought about,' Dietrich said. I commented.

in Science,   Creature, Posted by log1h_ik